Helped a friend with iOS 9.3 iPhones to upgrade OS X to El Capitan for better integration (albeit lacked thrill with some changes).

Personally not have any iOS 9 devices so research for this thread was useful for my upgrade planning to 10.11.4 (or 10.11.5). Annual OS X releases lack enough diversity among Beta testers so recent OS X releases have initially been a bit problematic: e.g. WiFi connectivity.

Not know how Faithlife application usage on OS X compares to general adoption of OS X, which typically has over 83 % using OS X 10.11 El Capitan or 10.10 Yosemite. Noticed OS X 10.9 Mavericks has some spikes up to 25 % usage this year.